Ruling on entering a church and praying in it for the sake of social courtesy

Question:
If a man prays with the Christians for the sake of social courtesy, or enters their church for the sake of social courtesy?

Answer:
Does he pray with the Christians for Isa? Or what? Who is he praying for?
Q: What kind of prayer with them?
The Shaykh: He does not pray with them, nor does he show them social courtesy, and he does not enter their churches, except out of need; for calling to Allah and guidance, or out of dire necessity, such as cold or rain or the like .
Q: What is the ruling on the one who does this?
The Shaykh: He is taught; it is said to him: This is not permissible. If he intended teaching and guidance, he should do so without this; he teaches them without praying with them.
And if he prays for Isa, he commits disbelief, may Allah keep us safe.
As for if he prays for Allah, it is a religious innovation, it is an error.
Q: If he has religious knowledge... is there no need to establish the argument against him?
The Shaykh: He is taught, he is taught; this is ignorance on his part, his knowledge is deficient; because the Messenger (peace and blessings be upon him) forbade imitating the polytheists, and he said: . So if he intends to call them, he calls them without imitation, without praying with them, without attending their gatherings for their festival or otherwise; he does not attend their gatherings, nor does he pray with them, nor does he participate in anything that is from their rituals.